Pests such as insects, arachnids, and acarines are detrimental to humans. Pests include pathogenic organisms that infest mammals and plants, such as those that infest or feed upon plants and livestock, thus causing economic loss or diminishment of plant crops, plant products, and livestock. For example, the glassy-winged sharpshooter is a pest that feeds on grape vines, thus diminishing the crop available for wine production. Other pests may infest structures such as dwellings, residences, hospitals, and commercial establishments, such as restaurants and retail stores. These pests may be detrimental to the structure, such as termites feeding on wooden beams, or simply be a nuisance to people who visit or live in infested buildings. Additionally, some pests are vectors for certain diseases that harm humans and non-human animals, including pets and livestock.
The transmission of vector-borne diseases through pests is a problem throughout the world and is best controlled through the control of those vectors. For example, the deer tick (Ixodes scapularis) may transmit Lyme disease to a host when feeding on the host's blood by passing an infectious microbe (Borrelia burgdorferi), which lives in the tick's midgut, into the host's bloodstream. A mosquito (Aedes aegypti), prevalent throughout many tropical and sub-tropical regions of the world, may transmit Dengue Fever, Yellow Fever, or encephalitis viruses to a host on which it feeds. The rat flea (Xenopsylla cheopis) is a vector for the microbe (Yersinia pestis) that causes the Plague.
Pest control is often difficult to achieve. Many pesticides are toxic to humans and animals and may pollute the environment. Hence, a number of commonly used pesticides, such as organophosphates, have been restricted or made commercially unavailable. Biopesticides derived from natural sources, such as plants, fungi, or other natural products, offer a safer alternative to chemically synthesized pesticides. Biopesticides generally have fewer health effects and can be better for the environment, but many biopesticides offer substantially weaker control of pests, or control only a limited spectrum of pests, while other biopesticides may be environmentally toxic. For example, pyrethrins—pesticides made from the extract of the chrysanthemum plant—control a wide variety of pests, but are very toxic to fish, such as bluegill and lake trout. Additionally, pests may become resistant to certain compounds after continued use; for example, insect resistance to pyrethrins already has been observed. Thus, new pest control agents offer an alternative for commonly used pesticides.
A need exists for effective pest control compositions capable of controlling (e.g., repelling or exterminating) a variety of pests, for example vectors of disease, which pest control compositions are relatively safe for humans, animals, plants, and the environment.